An issue or two ago, I wrote an article called Is life happy, or is it hell? This depends on your LPL! In this, I (obviously) described what the enzyme LPL (lipoprotein lipase) does. Now since LPL is our potential ‘fattening’ enzyme, you’ll probably want to know more about our ‘leaning’ enzyme, HSL (hormone sensitive lipase). In order to do this effectively, I’m going to use the furniture-moving analogy from Gary Taubes’s book “How we get fat and what to do about it”!

Macro, micro. Couches, chairs.

Foods are made up of three macronutrients, called carbohydrates, proteins and fats. Good quality fats break down into units called fatty acids, carbs into glucose (sugars) and protein into amino acids. The best energy form we can offer the body is fatty acids. These units are very small, but are packed with energy. In fact they offer double the value that the same unit of carb or protein will offer. Because they’re so small, they move in and out of our fat cells very easily. When we need to store them there because we already have enough energy in muscle and liver cells. The energy in those cells is ready to be used up by the body – we can just ‘un-store’ them when we run out of fuel and need a top-up. Let’s call these units chairs – functional, mobile and easily carried.

When we eat carbs, the process of breaking them down into their basic form produces a by-product called glycerol. Now glycerol does an interesting (and particularly nasty) thing – it attaches itself to fatty acids in the fat cells, causing triglycerides to form. Let’s call them couches – large and immobile.

So – a diet high in carbs will cause a lot of couches to be built in the fat cells. What’s the problem with this, you ask? Well, because they’re couches and not chairs, they can’t fit through the cell ‘doorway. So they’re stuck in the fat cells, causing fatness! The only way you can get rid of this fatness, is to disassemble the couches first, so that the fatty acids can flow out freely again and be used as a source of fuel by the body. Simple really.

Carbs = couches

So now you want to know how we can influence the number of couches vs chairs that are built inside our fat cells, right? Here’s how it goes: The more carbs you eat, the more glycerol you produce and the more couches you build. This leads to fatness. The less carbs you eat (instead, eating high quality fats), the fewer couches are formed and the more your chairs remain chairs.

Let’s not forget about insulin!

Another thing you need to know about eating carbs is that it stimulates the production of insulin. This is because carbs – especially simple and processed ones – mess with blood sugar levels by increasing these levels profoundly. This leads to the pancreas producing insulin to collect the excess sugar in the blood. This sugar is then shoved it into the cells for use as fuel. You’ll then only use the fatty acids you’ve held in reserve in your fat cells, after you’ve dealt with these carbs.

So high carbs = high insulin levels, and guess what high insulin levels lead to? It creates a mechanism in the fat cells that sucks in glucose. This, of course, only increases the number of glycerol molecules – therefore building ever more couches! And that’s not all – insulin also tells the liver not to burn fatty acids! They should rather send them back to your fat tissue and repackage these chairs into couches!

No room at the inn, so let’s build!

Argh! That’s still not all. If you’re running out of room in your fat cells, it’ll also work to create more fat cells so that you can store more couches.

I haven’t yet mentioned HSL and what this beautiful enzyme does is disassemble the couches that insulin helps create, so that we can use your chairs constructively. So I think it would be fair to say that we’d all rather like as much HSL activity on our fat cells as possible, yes?

I don’t need to tell you what this means, do I? Yep, a diet lower in carbs, but higher in good quality fat (and, as always, moderate-to-low amounts of high quality protein).